基于灰色关联法的泥石流灾害易发性影响因素分析——以甘肃舟曲瓜咋沟泥石流为例

Analisis on Hazard Evaluation of Debris Flow Based on Grey Relational Theory——A Case Study on the Debris Flow in Guaza Gully,Zhouqu,Gansu

2010年,甘肃舟曲"8·7"特大泥石流灾害给当地人民生命财产造成严重损失,泥石流的发生及其易发性程度受多种因素影响。为分析不同因素对泥石流灾害易发性影响程度,基于对甘肃舟曲瓜咋沟内不同泥石流沟道野外调查资料的总结与分析,运用层次分析法计算了泥石流灾害易发性指标,利用灰色关联度理论分析了泥石流灾害易发程度与各影响因素间关联程度。研究结果表明:运用层次分析法确定的泥石流灾害易发性程度与野外调研结果相一致;泥石流灾害的易发性受沟道内灾害点数量、主沟道坡降、日最大降雨量、植被覆盖率及汇水面积等的影响显著;沟道内灾害点数量和主沟道坡降,日最大降雨量、植被覆盖率及汇水面积,沟道长度、岸坡坡度及沟道宽度等分别对泥石流灾害易发性的影响程度较为接近;研究成果为类似地区泥流灾害防治工作部署具有一定指导作用。

Objectives： The＂8·7＂huge debris flow disaster in Guaza gully,Zhouqu,Gansu,has caused serious losses to local people＇s lives and property. This paper focus on the correlation degree between the susceptibility index of debris flow disaster and different influencing factors that is to identify the main influencing factors,which is to provide basis for prevention of debris flow hazards.Methods： Firstly,this paper summarizes and concludes the survey data with different debris flow gullies in Guaza gullies,which combined with＂8·7＂large debris flow disasters instance in Zhouqu County Gansu Province.Secondly,the susceptibility value of different mud-rock flow hazards gullies are calculated based on the AHP method. Finally,the influence degree of various environmental factors on the susceptibility index with the debris flow gullies is analyzed by the gray correlation method.Results： the vulnerability of debris flow disasters determined by AHP is consistent with the results of field investigation,that the AHP can be applied to the prediction of debris flow hazard. It has a significant impact on the susceptibility of mud-rock flow hazards from the number of geological disasters in channel,the average slope of gully,day maximum rainfall quantity,forest cover and catchment sizes. The susceptibility of debris flow disaster is relatively close which are affected by the number of disaster and the channel slope,the maximum rainfall quantity,vegetation coverage rate and catchment sizes,gully length,beach angle and channel width.Conclusions： The method of grey relational theory has been successfully applied to analysis the correlation degree between different influencing factors and the susceptibility of debris flow disaster,providing a guiding role for the prevention and control of mud-rock flow hazards in similar areas.